Mulching to protect soil
Mulching - Keep the Soil Covered
Mulch is any material that is spread over the soil to protect it, and both organic or nonorganic mulches can be used. There are several main things that mulch can do for the garden.
1. Protect the soil from water, wind and sun damage.
2. Reduce evaporation from soil.
3. Reduce weed pressure.
Here in the arid southwest, mulch is critically important for healthy soils. However all mulches may need maintenance. It's important to think about what your needs are when selecting mulches, especially if you plan to purchase mulch materials.
Mulching to protect soil
Guidelines for Selecting Mulches
Good mulches should allow water to penetrate and be able to resist being blown or washed away. If weed control is important, the mulch will need to be tough enough to keep weeds from sprouting through. Budget will need to be considered, especially for large areas, but there are free materials that can be used.
For farmers and gardeners who grow lots of food, choosing mulches that work with crop production will be important. Large rolls or sheets of mulch material can be easily installed and good for reducing weeds. Mulches should be compatible with the watering system and water should be accessible to the plant roots. They will also need to work with seeding and transplanting.
Options for mulch material
Organic Mulches
The least expensive mulches may be laying around the garden or surrounding property. Crushed leaves, grass clippings, straw or pine needles can be used to provide mulch that will eventually break down into soil. The downside is that they may be too light to resist wind, can harbor pests and will need replaced as they break down, usually needing some kind of additional barrier underneath for weed suppression. Some attractive options are available for purchase such as tinted bark or pecan shells. Note that straw is likely to have herbicide residue if you haven't grown it or sourced from someone following organic practices.
Paper & Biodegradable Fibers
Paper makes a nice if temporary barrier to weeds and pests, usually needing covered with heavy top layers to resist wind. Avoid paper with coatings, shiny finishes and bright colors. Rolls of mulch paper can be purchased and are easier to use than newspaper. I have also used burlap that I was gifted which worked very well for establishing paths. Natural packing materials such as newsprint and shredded wood can have a second life as mulch.
Plastic Mulches
Farms commonly use sheets of plastic fabrics that provide a high level of protection from weeds while sheltering drip lines underneath. Durable, UV-resistant products can be taken up at the end of the season and reused. The cost may be off set by the reduction in weeding labor and the water conservation.
For the home garden they are less practical in my opinion. They can leach chemicals, are unattractive and must be physically removed to avoid plastic shreds from everywhere. I consider them a tool in the toolbox, but generally avoid plastic products in the garden.
Other Mulch Materials
Rocks can be used to protect soil and create favorable soil microclimates. They can slow the heating of the soil during the day and release stored heat through the night, and can retain soil moisture. These and a number of other non-toxic and abundant materials can be used to mulch or create berms and barriers around the garden that will shelter plants from wind and help with water retention.